Method and apparatus for expansion sealing concentric tubular structures

Abstract

A device and method for sealing a first cylinder in a fixed position inside a second concentric cylinder. The inner cylinder has an annular depression in its wall at the point of sealant placement, which causes the wall of the inner cylinder to intrude inwardly. The depression is filled with a partially compressible fluid and is covered over by a malleable/ductile sleeve. The inner cylinder is placed within the outer cylinder with the covered annular depression positioned at the desired sealing point. A cylindrical displacement device is directed through the inside of the inner cylinder where it encounters the intrusion of the annular depression. The displacement device is forced past the annular intrusion and pushes the wall outward. The partially compressible fluid is forced to expand outward under the malleable/ductile cover in a manner that intrudes into the annular space between the inner cylinder and the outer cylinder and into contact with the outer cylinder. The partially compressible fluid has a residual energy sufficient to maintain the sealing element in contact with the outer cylinder.

We claim:  
     
       1. An apparatus for sealing a first tubular element in a fixed position with respect to a second, concentric tubular element, the apparatus comprising: 
       a first tubular element, said tubular element having a length generally greater than its diameter and having a generally circular cross-section, said first tubular element comprising a cylindrical wall, said cylindrical wall being generally linear and parallel to a longitudinal axis of said tubular element, said cylindrical wall being annularly depressed into an interior of said first tubular element in at least one longitudinal location thereon, said annular depression forming a ring-shaped cavity on an exterior of said first tubular element and a ring-shaped intrusion into said interior of said first tubular element;  
       a quantity of a partially compressible fluid positioned in said annular depression in said first tubular element;  
       a malleable/ductile cover sleeve positioned around said first tubular member and covering said partially compressible fluid positioned within said annular depression;  
       a displacement device positioned within said first tubular element and having an outside dimension incrementally less than said inside diameter of said first tubular element; and  
       means for exerting a longitudinal force on said displacement device so as to direct said displacement device through said first tubular element and past said ring-shaped intrusion into said interior of said first tubular element, said displacement device forcing an expansion of said cylindrical walls of said first tubular element at said annular depression thereby forcing said partially compressible fluid against said malleable/ductile sleeve and expanding said malleable/ductile sleeve into an annular space between said first tubular element and said second tubular element to at least a point where said expanded sleeve contacts an inside wall surface of said second tubular member.  
     
     
       2. The apparatus of  claim 1  wherein said annular depression formed in said first tubular element is further defined by a first annular edge and a second annular edge, a depth of said annular depression adjacent said first annular edge being generally greater than a depth of said annular depression adjacent said second annular edge. 
     
     
       3. The apparatus of  claim 1  wherein said partially compressible fluid comprises a thermoplastic compound. 
     
     
       4. The apparatus of  claim 1  wherein said partially compressible fluid comprises a combination of a high temperature elastomer compound and a fluid elastomer compound. 
     
     
       5. The apparatus of  claim 4  wherein said partially compressible fluid comprises a combination of a silicon rubber compound and a silicon fluid compound. 
     
     
       6. The apparatus of  claim 4  wherein said partially compressible fluid comprises a combination of a high temperature elastomer compound and a quantity of microspheres. 
     
     
       7. The apparatus of  claim 1  wherein said partially compressible fluid comprises a low density polyethylene compound. 
     
     
       8. The apparatus of  claim 1  wherein said displacement device comprises a solid cylindrical wedge having an outer diameter less than an inner diameter of said first tubular element. 
     
     
       9. The apparatus of  claim 1  wherein said displacement device comprises a mechanical roller assembly having an overall diameter less than an inner diameter of said first tubular element. 
     
     
       10. An apparatus for sealing a first tubular element in a fixed position with respect to a second, concentric tubular element, the apparatus comprising: 
       a first tubular element, said tubular element having a length generally greater than its diameter and having a generally circular cross-section, said first tubular element comprising a cylindrical wall, said cylindrical wall being generally linear and parallel to a longitudinal axis of said tubular element, said cylindrical wall having a plurality of ports arranged at a longitudinal position thereon, said ports providing liquid communication through said cylindrical wall of said first tubular element;  
       a quantity of a partially compressible fluid comprising a thermoplastic compound;  
       a malleable/ductile cover sleeve positioned around said first cylinder and covering said plurality of ports positioned in said cylindrical wall of said first cylinder; and  
       means for directing said partially compressible fluid under pressure through said plurality of ports thereby forcing said partially compressible fluid against said malleable/ductile sleeve and expanding said malleable/ductile sleeve into an annular space between said first tubular element and said second tubular element to at least a point where said expanded sleeve contacts an inside wall surface of said second tubular member.  
     
     
       11. An apparatus for sealing a first tubular element in a fixed position with respect to a second, concentric tubular element, the apparatus comprising: 
       a first tubular element, said tubular element having a length generally greater than its diameter and having a generally circular cross-section, said first tubular element comprising a cylindrical wall, said cylindrical wall being generally linear and parallel to a longitudinal axis of said tubular element, said cylindrical wall having a plurality of ports arranged at a longitudinal position thereon, said ports providing liquid communication through said cylindrical wall of said first tubular element;  
       a quantity of a partially compressible fluid comprising a low density polyethylene compound;  
       a malleable/ductile cover sleeve positioned around said first cylinder and covering said plurality of ports positioned in said cylindrical wall of said first cylinder; and  
       means for directing said partially compressible fluid under pressure through said plurality of ports thereby forcing said partially compressible fluid against said malleable/ductile sleeve and expanding said malleable/ductile sleeve into an annular space between said first tubular element and said second tubular element to at least a point where said expanded sleeve contacts an inside wall surface of said second tubular member.  
     
     
       12. An apparatus for sealing a first tubular element in a fixed position with respect to a second, concentric tubular element, the apparatus comprising: 
       a first tubular element, said tubular element having a length generally greater than its diameter and having a generally circular cross-section, said first tubular element comprising a cylindrical wall, said cylindrical wall being generally linear and parallel to a longitudinal axis of said tubular element, said cylindrical wall having a plurality of ports arranged at a longitudinal position thereon, said ports providing liquid communication through said cylindrical wall of said first tubular element;  
       a quantity of a partially compressible fluid comprising a combination of a high temperature elastomer compound and a fluid elastomer compound;  
       a malleable/ductile cover sleeve positioned around said first cylinder and covering said plurality of ports positioned in said cylindrical wall of said first cylinder; and  
       means for directing said partially compressible fluid under pressure through said plurality of ports thereby forcing said partially compressible fluid against said malleable/ductile sleeve and expanding said malleable/ductile sleeve into an annular space between said first tubular element and said second tubular element to at least a point where said expanded sleeve contacts an inside wall surface of said second tubular member.  
     
     
       13. The apparatus of  claim 12  wherein said partially compressible fluid comprises a combination of a silicon rubber compound and a silicon fluid compound. 
     
     
       14. The apparatus of  claim 12  wherein said partially compressible fluid comprises a combination of a high temperature elastomer compound and a quantity of microspheres. 
     
     
       15. An apparatus for sealing a first tubular element in a fixed position with respect to a second, concentric tubular element, the apparatus comprising: 
       a first tubular element, said tubular element having a length generally greater than its diameter and having a generally circular cross-section, said first tubular element comprising a cylindrical wall, said cylindrical wall being generally linear and parallel to a longitudinal axis of said tubular element, said cylindrical wall having an annular inclusion formed in an end thereof, said annular inclusion extending into said cylindrical wall in a direction generally parallel to said longitudinal axis of said tubular element, said annular inclusion forming a ring-shaped cavity interior to said first tubular element and a resultant ring-shaped intrusion into said interior of said first tubular element, said ring-shaped cavity enclosed by an outer subwall formed from said cylindrical wall and an inner subwall formed from said cylindrical wall;  
       a quantity of a partially compressible fluid positioned in said annular inclusion in said first tubular element between said inner and outer subwalls thereof;  
       a displacement device positioned within said first tubular element and having an outside dimension incrementally less than said inside diameter of said first tubular element; and  
       means for exerting a longitudinal force on said displacement device so as to direct said displacement device through said first tubular element and past said ring-shaped intrusion into said interior of said first tubular element, said displacement device forcing an expansion of said inner subwall of said cylindrical wall of said first tubular element at said annular inclusion thereby forcing said partially compressible fluid against said outer subwall and expanding said outer subwall into an annular space between said first tubular element and said second tubular element to at least a point where said expanded outer subwall contacts an inside wall surface of said second tubular member.  
     
     
       16. The apparatus of  claim 15  further comprising an O-ring seal positioned in said annular inclusion and serving to facilitate the retention of said partially compressible fluid therein. 
     
     
       17. The apparatus of  claim 16  further comprising a rigid ring seal positioned in said annular inclusion and serving to facilitate the retention of said partially compressible fluid therein, said rigid ring seal being welded to said outer subwall and to said inner subwall. 
     
     
       18. A method for sealing a first tubular element in a fixed position with respect to a second, concentric tubular element, the method comprising the steps of: 
       forming at least one annular depression into a wall of said first tubular element in at least one location thereon, said annular depression forming a ring-shaped cavity on an exterior of said first tubular element and a ring-shaped intrusion into an interior of said first tubular element;  
       positioning a quantity of a partially compressible fluid into said annular depression formed in said first tubular element;  
       positioning a malleable/ductile cover sleeve around said first tubular element and covering said partially compressible fluid positioned within said annular depression;  
       introducing said first tubular element with said partially compressible fluid and said malleable/ductile cover sleeve into said second tubular element;  
       positioning said malleable/ductile cover sleeve, in place on said first tubular element at a point within said second tubular element where said sealing is to be placed;  
       introducing a displacement device into said first tubular element and positioning said displacement device adjacent to said ring-shaped intrusion within said first tubular element; and  
       exerting a longitudinal force on said displacement device so as to direct said displacement device through said first tubular element and past said ring-shaped intrusion, said displacement device forcing an expansion of said cylindrical walls of said first tubular element at said annular depression thereby forcing said partially compressible fluid against said malleable/ductile sleeve and expanding said malleable/ductile sleeve into an annular space between said first tubular element and said second tubular element to at least a point where said expanded sleeve contacts said inside surface of said second tubular element.  
     
     
       19. The method of  claim 18  wherein said step of forming at least one annular depression comprises forming a shallow portion of said depression and an adjacent deep portion of said depression and wherein said step of introducing a displacement device into said first tubular element comprises first introducing said displacement device against said shallow portion of said depression and progressively introducing said displacement device against said deep portion of said depression.